From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>,
Will Deacon <will.deacon@arm.com>, Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Waiman Long <waiman.long@hp.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Alex Shi <alex.shi@linaro.org>, Andi Kleen <andi@firstfloor.org>,
Michel Lespinasse <walken@google.com>,
Davidlohr Bueso <davidlohr.bueso@hp.com>,
Matthew R Wilcox <matthew.r.wilcox@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Rik van Riel <riel@redhat.com>,
Peter Hurley <peter@hurleysoftware.com>,
Raghavendra
Subject: Re: [PATCH v6 4/5] MCS Lock: Barrier corrections
Date: Thu, 21 Nov 2013 05:18:06 -0800 [thread overview]
Message-ID: <20131121131806.GQ4138@linux.vnet.ibm.com> (raw)
In-Reply-To: <20131121104503.GB10022@twins.programming.kicks-ass.net>
On Thu, Nov 21, 2013 at 11:45:03AM +0100, Peter Zijlstra wrote:
> On Wed, Nov 20, 2013 at 08:53:33PM -0800, Paul E. McKenney wrote:
> > The other option is to weaken lock semantics so that unlock-lock no
> > longer implies a full barrier, but I believe that we would regret taking
> > that path. (It would be OK by me, I would just add a few smp_mb()
> > calls on various slowpaths in RCU. But...)
>
> Please no, I know we rely on it in a number of places, I just can't
> remember where all those were :/
;-) ;-) ;-)
Yeah, I would also have to overprovision smp_mb()s in a number of
places. Then again, I know that I don't rely on this on any of
RCU's fastpaths.
Thanx, Paul
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WARNING: multiple messages have this Message-ID (diff)
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>,
Will Deacon <will.deacon@arm.com>, Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Waiman Long <waiman.long@hp.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Alex Shi <alex.shi@linaro.org>, Andi Kleen <andi@firstfloor.org>,
Michel Lespinasse <walken@google.com>,
Davidlohr Bueso <davidlohr.bueso@hp.com>,
Matthew R Wilcox <matthew.r.wilcox@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Rik van Riel <riel@redhat.com>,
Peter Hurley <peter@hurleysoftware.com>,
Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
George Spelvin <linux@horizon.com>,
"H. Peter Anvin" <hpa@zytor.com>, Arnd Bergmann <arnd@arndb.de>,
Aswin Chandramouleeswaran <aswin@hp.com>,
Scott J Norton <scott.norton@hp.com>,
"Figo.zhang" <figo1802@gmail.com>
Subject: Re: [PATCH v6 4/5] MCS Lock: Barrier corrections
Date: Thu, 21 Nov 2013 05:18:06 -0800 [thread overview]
Message-ID: <20131121131806.GQ4138@linux.vnet.ibm.com> (raw)
In-Reply-To: <20131121104503.GB10022@twins.programming.kicks-ass.net>
On Thu, Nov 21, 2013 at 11:45:03AM +0100, Peter Zijlstra wrote:
> On Wed, Nov 20, 2013 at 08:53:33PM -0800, Paul E. McKenney wrote:
> > The other option is to weaken lock semantics so that unlock-lock no
> > longer implies a full barrier, but I believe that we would regret taking
> > that path. (It would be OK by me, I would just add a few smp_mb()
> > calls on various slowpaths in RCU. But...)
>
> Please no, I know we rely on it in a number of places, I just can't
> remember where all those were :/
;-) ;-) ;-)
Yeah, I would also have to overprovision smp_mb()s in a number of
places. Then again, I know that I don't rely on this on any of
RCU's fastpaths.
Thanx, Paul
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
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next prev parent reply other threads:[~2013-11-21 13:18 UTC|newest]
Thread overview: 239+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1384885312.git.tim.c.chen@linux.intel.com>
2013-11-20 1:37 ` [PATCH v6 0/5] MCS Lock: MCS lock code cleanup and optimizations Tim Chen
2013-11-20 1:37 ` Tim Chen
2013-11-20 1:37 ` Tim Chen
2013-11-20 10:19 ` Will Deacon
2013-11-20 10:19 ` Will Deacon
2013-11-20 12:50 ` Paul E. McKenney
2013-11-20 12:50 ` Paul E. McKenney
2013-11-20 17:00 ` Will Deacon
2013-11-20 17:00 ` Will Deacon
2013-11-20 17:14 ` Paul E. McKenney
2013-11-20 17:14 ` Paul E. McKenney
2013-11-20 17:00 ` Tim Chen
2013-11-20 17:00 ` Tim Chen
2013-11-20 17:16 ` Paul E. McKenney
2013-11-20 17:16 ` Paul E. McKenney
2013-11-20 1:37 ` [PATCH v6 1/5] MCS Lock: Restructure the MCS lock defines and locking code into its own file Tim Chen
2013-11-20 1:37 ` Tim Chen
2013-11-20 1:37 ` Tim Chen
2013-11-20 1:37 ` [PATCH v6 2/5] MCS Lock: optimizations and extra comments Tim Chen
2013-11-20 1:37 ` Tim Chen
2013-11-20 1:37 ` Tim Chen
2013-11-20 1:37 ` [PATCH v6 3/5] MCS Lock: Move mcs_lock/unlock function into its own file Tim Chen
2013-11-20 1:37 ` Tim Chen
2013-11-20 1:37 ` Tim Chen
2013-11-20 1:37 ` [PATCH v6 4/5] MCS Lock: Barrier corrections Tim Chen
2013-11-20 1:37 ` Tim Chen
2013-11-20 1:37 ` Tim Chen
2013-11-20 15:31 ` Paul E. McKenney
2013-11-20 15:31 ` Paul E. McKenney
2013-11-20 15:31 ` Paul E. McKenney
2013-11-20 15:46 ` Will Deacon
2013-11-20 15:46 ` Will Deacon
2013-11-20 17:14 ` Paul E. McKenney
2013-11-20 17:14 ` Paul E. McKenney
2013-11-20 18:43 ` Tim Chen
2013-11-20 18:43 ` Tim Chen
2013-11-20 19:06 ` Paul E. McKenney
2013-11-20 19:06 ` Paul E. McKenney
2013-11-20 20:36 ` Tim Chen
2013-11-20 20:36 ` Tim Chen
2013-11-20 21:44 ` Paul E. McKenney
2013-11-20 21:44 ` Paul E. McKenney
2013-11-20 23:51 ` Tim Chen
2013-11-20 23:51 ` Tim Chen
2013-11-21 4:53 ` Paul E. McKenney
2013-11-21 4:53 ` Paul E. McKenney
2013-11-21 10:17 ` Will Deacon
2013-11-21 10:17 ` Will Deacon
2013-11-21 13:16 ` Paul E. McKenney
2013-11-21 13:16 ` Paul E. McKenney
2013-11-21 10:45 ` Peter Zijlstra
2013-11-21 10:45 ` Peter Zijlstra
2013-11-21 13:18 ` Paul E. McKenney [this message]
2013-11-21 13:18 ` Paul E. McKenney
2013-11-21 22:27 ` Linus Torvalds
2013-11-21 22:27 ` Linus Torvalds
2013-11-21 22:52 ` Paul E. McKenney
2013-11-21 22:52 ` Paul E. McKenney
2013-11-22 0:09 ` Linus Torvalds
2013-11-22 0:09 ` Linus Torvalds
2013-11-22 4:08 ` Paul E. McKenney
2013-11-22 4:08 ` Paul E. McKenney
2013-11-22 4:25 ` Linus Torvalds
2013-11-22 4:25 ` Linus Torvalds
2013-11-22 6:23 ` Paul E. McKenney
2013-11-22 6:23 ` Paul E. McKenney
2013-11-22 15:16 ` Ingo Molnar
2013-11-22 15:16 ` Ingo Molnar
2013-11-22 18:49 ` Paul E. McKenney
2013-11-22 18:49 ` Paul E. McKenney
2013-11-22 19:06 ` Linus Torvalds
2013-11-22 19:06 ` Linus Torvalds
2013-11-22 20:06 ` Paul E. McKenney
2013-11-22 20:06 ` Paul E. McKenney
2013-11-22 20:09 ` Linus Torvalds
2013-11-22 20:09 ` Linus Torvalds
2013-11-22 20:37 ` Paul E. McKenney
2013-11-22 20:37 ` Paul E. McKenney
2013-11-22 21:01 ` Linus Torvalds
2013-11-22 21:01 ` Linus Torvalds
2013-11-22 21:52 ` Paul E. McKenney
2013-11-22 21:52 ` Paul E. McKenney
2013-11-22 22:19 ` Linus Torvalds
2013-11-22 22:19 ` Linus Torvalds
2013-11-23 0:25 ` Paul E. McKenney
2013-11-23 0:25 ` Paul E. McKenney
2013-11-23 0:42 ` Linus Torvalds
2013-11-23 0:42 ` Linus Torvalds
2013-11-23 1:36 ` Paul E. McKenney
2013-11-23 1:36 ` Paul E. McKenney
2013-11-23 2:11 ` Linus Torvalds
2013-11-23 2:11 ` Linus Torvalds
2013-11-23 4:05 ` Paul E. McKenney
2013-11-23 4:05 ` Paul E. McKenney
2013-11-23 11:24 ` Ingo Molnar
2013-11-23 11:24 ` Ingo Molnar
2013-11-23 17:06 ` Paul E. McKenney
2013-11-23 17:06 ` Paul E. McKenney
2013-11-26 12:02 ` Ingo Molnar
2013-11-26 12:02 ` Ingo Molnar
2013-11-26 19:28 ` Paul E. McKenney
2013-11-26 19:28 ` Paul E. McKenney
2013-11-23 20:21 ` Linus Torvalds
2013-11-23 20:21 ` Linus Torvalds
2013-11-23 20:39 ` Linus Torvalds
2013-11-23 20:39 ` Linus Torvalds
2013-11-25 12:09 ` Peter Zijlstra
2013-11-25 12:09 ` Peter Zijlstra
2013-11-25 17:18 ` Will Deacon
2013-11-25 17:18 ` Will Deacon
2013-11-25 17:56 ` Paul E. McKenney
2013-11-25 17:56 ` Paul E. McKenney
2013-11-25 17:54 ` Paul E. McKenney
2013-11-25 17:54 ` Paul E. McKenney
2013-11-23 21:29 ` Peter Zijlstra
2013-11-23 21:29 ` Peter Zijlstra
2013-11-23 22:24 ` Linus Torvalds
2013-11-23 22:24 ` Linus Torvalds
2013-11-25 17:53 ` Paul E. McKenney
2013-11-25 17:53 ` Paul E. McKenney
2013-11-25 18:21 ` Peter Zijlstra
2013-11-25 18:21 ` Peter Zijlstra
2013-11-21 11:03 ` Peter Zijlstra
2013-11-21 11:03 ` Peter Zijlstra
2013-11-21 12:56 ` Peter Zijlstra
2013-11-21 12:56 ` Peter Zijlstra
2013-11-21 13:20 ` Paul E. McKenney
2013-11-21 13:20 ` Paul E. McKenney
2013-11-21 17:25 ` Paul E. McKenney
2013-11-21 17:25 ` Paul E. McKenney
2013-11-21 21:52 ` Peter Zijlstra
2013-11-21 21:52 ` Peter Zijlstra
2013-11-21 22:18 ` Paul E. McKenney
2013-11-21 22:18 ` Paul E. McKenney
2013-11-22 15:58 ` Peter Zijlstra
2013-11-22 15:58 ` Peter Zijlstra
2013-11-22 18:26 ` Paul E. McKenney
2013-11-22 18:26 ` Paul E. McKenney
2013-11-22 18:51 ` Peter Zijlstra
2013-11-22 18:51 ` Peter Zijlstra
2013-11-22 18:59 ` Paul E. McKenney
2013-11-22 18:59 ` Paul E. McKenney
2013-11-25 17:35 ` Peter Zijlstra
2013-11-25 17:35 ` Peter Zijlstra
2013-11-25 18:02 ` Paul E. McKenney
2013-11-25 18:02 ` Paul E. McKenney
2013-11-25 18:24 ` Peter Zijlstra
2013-11-25 18:24 ` Peter Zijlstra
2013-11-25 18:34 ` Tim Chen
2013-11-25 18:34 ` Tim Chen
2013-11-25 18:27 ` Peter Zijlstra
2013-11-25 18:27 ` Peter Zijlstra
2013-11-25 23:52 ` Paul E. McKenney
2013-11-25 23:52 ` Paul E. McKenney
2013-11-26 9:59 ` Peter Zijlstra
2013-11-26 9:59 ` Peter Zijlstra
2013-11-26 17:11 ` Paul E. McKenney
2013-11-26 17:11 ` Paul E. McKenney
2013-11-26 17:18 ` Peter Zijlstra
2013-11-26 17:18 ` Peter Zijlstra
2013-11-26 19:00 ` Linus Torvalds
2013-11-26 19:00 ` Linus Torvalds
2013-11-26 19:20 ` Paul E. McKenney
2013-11-26 19:20 ` Paul E. McKenney
2013-11-26 19:32 ` Linus Torvalds
2013-11-26 19:32 ` Linus Torvalds
2013-11-26 22:51 ` Paul E. McKenney
2013-11-26 22:51 ` Paul E. McKenney
2013-11-26 23:58 ` Linus Torvalds
2013-11-26 23:58 ` Linus Torvalds
2013-11-27 0:21 ` Thomas Gleixner
2013-11-27 0:21 ` Thomas Gleixner
2013-11-27 0:39 ` Paul E. McKenney
2013-11-27 0:39 ` Paul E. McKenney
2013-11-27 1:05 ` Linus Torvalds
2013-11-27 1:05 ` Linus Torvalds
2013-11-27 1:31 ` Paul E. McKenney
2013-11-27 1:31 ` Paul E. McKenney
2013-11-27 10:16 ` Will Deacon
2013-11-27 10:16 ` Will Deacon
2013-11-27 17:11 ` Paul E. McKenney
2013-11-27 17:11 ` Paul E. McKenney
2013-11-28 11:40 ` Will Deacon
2013-11-28 11:40 ` Will Deacon
2013-11-28 17:38 ` Paul E. McKenney
2013-11-28 17:38 ` Paul E. McKenney
2013-11-28 18:03 ` Will Deacon
2013-11-28 18:03 ` Will Deacon
2013-11-28 18:27 ` Paul E. McKenney
2013-11-28 18:27 ` Paul E. McKenney
2013-11-28 18:53 ` Will Deacon
2013-11-28 18:53 ` Will Deacon
2013-11-28 19:50 ` Paul E. McKenney
2013-11-28 19:50 ` Paul E. McKenney
2013-11-29 16:17 ` Will Deacon
2013-11-29 16:17 ` Will Deacon
2013-11-29 16:44 ` Linus Torvalds
2013-11-29 16:44 ` Linus Torvalds
2013-11-29 18:18 ` Will Deacon
2013-11-29 18:18 ` Will Deacon
2013-11-30 17:38 ` Paul E. McKenney
2013-11-30 17:38 ` Paul E. McKenney
2013-11-26 19:21 ` Peter Zijlstra
2013-11-26 19:21 ` Peter Zijlstra
2013-11-27 16:58 ` Oleg Nesterov
2013-11-27 16:58 ` Oleg Nesterov
2013-11-26 23:08 ` Benjamin Herrenschmidt
2013-11-26 23:08 ` Benjamin Herrenschmidt
2013-11-25 23:55 ` H. Peter Anvin
2013-11-25 23:55 ` H. Peter Anvin
2013-11-26 3:16 ` Paul E. McKenney
2013-11-26 3:16 ` Paul E. McKenney
2013-11-27 0:46 ` H. Peter Anvin
2013-11-27 0:46 ` H. Peter Anvin
2013-11-27 1:07 ` Linus Torvalds
2013-11-27 1:07 ` Linus Torvalds
2013-11-27 1:27 ` Paul E. McKenney
2013-11-27 1:27 ` Paul E. McKenney
2013-11-27 2:59 ` H. Peter Anvin
2013-11-27 2:59 ` H. Peter Anvin
2013-11-25 18:52 ` H. Peter Anvin
2013-11-25 18:52 ` H. Peter Anvin
2013-11-25 22:58 ` Tim Chen
2013-11-25 22:58 ` Tim Chen
2013-11-25 23:28 ` H. Peter Anvin
2013-11-25 23:28 ` H. Peter Anvin
2013-11-25 23:51 ` Paul E. McKenney
2013-11-25 23:51 ` Paul E. McKenney
2013-11-25 23:36 ` Paul E. McKenney
2013-11-25 23:36 ` Paul E. McKenney
2013-12-04 21:26 ` Andi Kleen
2013-12-04 21:26 ` Andi Kleen
2013-12-04 22:07 ` Paul E. McKenney
2013-12-04 22:07 ` Paul E. McKenney
2013-11-21 13:19 ` Paul E. McKenney
2013-11-21 13:19 ` Paul E. McKenney
2013-11-20 1:37 ` [PATCH v6 5/5] MCS Lock: Allows for architecture specific mcs lock and unlock Tim Chen
2013-11-20 1:37 ` Tim Chen
2013-11-20 1:37 ` Tim Chen
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